Multilocus genotypes of two strains of Neisseria meningitidis and their presumed variants obtained upon subcultivation

Loss of sulfonamide resistance and endotoxin liberation have been described in two strains of Neisseria meningitidis serogroup B, upon subcultivation every 1 to 2 months over an 18-month period. Subsequently, the two laboratory variants, designated 270E- and 840E-, were also found to differ from the parent strains, 270E+ and 840E+, in serotype, outer membrane protein pattern, and virulence in mice. We report here the multilocus genotypes determined by enzyme electrophoresis, of the four isolates 270E+, 270E-, 840E+, and 840E-, and demonstrate that 270E- and 840E- strains could not have originated from subcultivation of 270E+ and 840E+, respectively, but that a mix-up of strains has occurred.     

Differential rates of metabolic activation and detoxication of the food mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine by different cytochrome P450 enzymes

Rat liver microsomes metabolized the food mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) to the genotoxic metabolite 2-hydroxamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (2-hydroxamino-PhIP) and to the detoxified product 2-amino-4'-hydroxy-1-methyl-6-phenylimidazo[4,5-b]pyridine (4'-hydroxy-PhIP). A 25-fold higher rate of metabolism was measured in microsomes from polychlorinated-biphenyl-treated rats (94 nmol/mg proteins/30 min) in comparison with those from untreated rats. Other effective inducers of PhIP metabolism were beta-naphthoflavone and isosafrole (ISF), whereas phenobarbital was ineffective. About twice as much 2-hydroxamino-PhIP as 4'-hydroxy-PhIP was formed in microsomes irrespective of the inducer the rats had been treated with. The metabolism was dependent on NADPH and was abolished by the cytochrome P450 inhibitor alpha-naphthoflavone. In a reconstituted enzyme system purified rat cytochrome P450 IA2 (P450ISF-G) had the highest N-hydroxylation rate (30 nmol/nmol P450/30 min) closely followed by the rat cytochrome P450 IA1 (P450BNF-B). Less activity was seen with rat P450 IIC11 (P450UT-A) and rabbit P450 IA2 (P450 LM4). Rat P450 IIE1 (P450j), P450 IIB1 (P450PB-B) and rabbit P450 IIB4 (P450 LM-2) and P450 IIE1 (P450 LM3a) were essentially inactive. Rat P450 IA1 (P450BNF-B) produced five times more 4'-hydroxy-PhIP (32 +/- 2 nmol/nmol P450/30 min) than did P450 IA2 (P450ISF-G). Hence, the measured ratio of activation to detoxication for rat P450 IA2 (P450ISF-G) enzyme was 7-fold higher than that of the other active P450 enzymes.     

The effect of meditation on shooting performance.

OBJECTIVE: To study effects of meditation on the shooting performance. METHODS: 25 elite shooters were investigated in an independent groups design. The results in standardised test shootings indoors and in ordinary competitions outdoors were assessed before and after regular meditation training for the experimental group. The experience of tension during the test shootings was self recorded on a visual analogue scale (VAS). RESULTS: The competition results in the outdoor season (1993), just after the meditation training period, compared with the results the previous season (1992), were better in the meditation group (P < 0.05). No significant difference between the groups was observed in the test shootings before and after the relaxation intervention. A significant association was shown between low tension and the results in the test shootings (correlation r = 0.42, P < 0.0001; Wilcoxon rank sum test, z = -3.36, P < 0.001); 18% (= r2) of the variance in performance was explained by tension. CONCLUSIONS: Meditation may enhance competitive shooting performance.     

Post-irradiation somnolence syndrome in an adult patient following allogeneic bone marrow transplantation.

Neurologic disturbances are common following the intensive chemotherapy and radiotherapy of bone marrow transplantation (BMT) conditioning regimens. The somnolence syndrome, which occurs in most children treated for leukemia with prophylactic cranial irradiation, has previously not been reported following BMT. This syndrome consists of transient lethargy, irritability, headaches, low grade fevers, gastrointestinal disturbances and depression. We report the case of a 38-year-old female with acute non-lymphocytic leukemia who developed symptoms typical of the somnolence syndrome 8 weeks following 1320 cGy total body irradiation and cyclophosphamide conditioning. Encephalographic findings were consistent with the syndrome, and no additional infectious or metabolic disorders could be identified. As predicted by the pediatric experience, the symptoms were transient, resolving following steroid and anti-depressant therapy. Among patients undergoing radiation based conditioning regimens, especially those not receiving concurrent steroid therapy, the appearance of post-transplantation somnolence may be an expression of this syndrome.     

The effects of two different crystalloid cardioplegic solutions on cultured human endothelial cells

The effects on cultured human endothelial cells of incubation with two standard crystalloid cardioplegic solutions (St. Thomas' and Bretschneider's) for one or five hours at 10 degrees C or 20 degrees C were studied. The cells were prelabelled with 51Cr and cell injury was measured by release of 51Cr, cell detachment, and by electron microscopy. The injury was also studied after a rewarming period of 35 minutes in cell culture medium at 37 degrees C. Endothelial cells incubated with cell culture medium, but otherwise treated in a similar way, served as controls. Both cardioplegic solutions caused significantly greater release of 51Cr than cell culture medium when incubated at 10 degrees C or 20 degrees C. The Bretschneider's solution induced slightly more release of 51Cr than did the St. Thomas' solution. The cells did not become detached during incubation. Electron microscopy of the cells after 5 hours with the cardioplegic solutions at 10 degrees C revealed contraction of the cells, mild intracellular oedema, swelling of mitochondria, and blebs or craters on the luminal surface of the cells. After rewarming in culture medium for 35 min the cells were not contracted and showed only minimal signs of injury, indicating a rapid and nearly complete reversibility of the changes. The present observations indicate that cultured endothelial cells get some protection, albeit not optimal, from the two crystalloid cardioplegic solutions tested. The presence of procaine-CL increased the injurious effect of the solutions.